Quick staling

Hi,

I've been baking for a while, including with a sourdough started I've made from scratch which works pretty well producing breads with nice holes, and yeasted breads using instant yeast.

I work with two basic bread recipes - a 70% whole wheat sourdough bread with nothing but starter, flour, salt and water) and Challah (30% whole wheat, 70% AP flour with about 10.5-11 percent protein, about a tablespoon of wheat gluten - since where I can't get bread flour, sunflower oil, eggs, honey, instant yeast). From time to time I make small changes to the first recipe - changing the ration of ww to ap flour.

No matter what I do the bread seems to have a pretty short life span. A couple of hours after being baked the bread will have the appearance of being a bit on the stale side. When cutting a slice instead of making a clean fresh cut, white greyish crumbs will appear, and the same coloration will appear on the surface of the bread. The color seems off somehow. It's as if my bread practically goes straight from the oven to being stale without being fresh for some interval of time in between.

Another phenomenon which may be connected is that my loaves come out very heavy, even when they have moderately sized holes in them. The crumb texture between these holes is dense and moist. When I toast a slice of bread it takes longer for it to toast than for store bought bread.

I've been trying all kinds of adjustments to the recipes - level of hydration, baking time etc. but with no luck.

If this is familiar to anyone or if anyone can give me a pointer on the matter, it would be appreciated.